Mir SSTV Experiment

["Miles Mann" <Miles_Mann@xxxxxxxxxx>]

To:       ARISS and AMSAT Members
From:          Miles Mann WF1F
Subject:  Mir SSTV Experiments
Date:          June 2, 1998


Hi everyone:

Many of you have probably heard rumors about the Mir SSTV project.  This
project first began with a phone call from Farrell Winder in May 1997.
Shortly after that call Mirex team began working on designing and building
a flight quality SSTV system which could be used on board the Russian Space
Station Mir.  AMSAT-NA was asked on at least two occasions if they were
interested in participating in the SSTV project.  The comments received
back from Bill Tynan were 

?Thanks for the suggestions.  I will pass them
along to the Board for consideration?.  Mirex was more than willing to work
with other satellite groups, but it seemed that no one was really
interested other than Mirex and Moscow.  Mirex began working out the
details with Moscow.  By April 1998 four flight ready systems were in the
final stages of testing and a tentative launch date had been discussed. On
May 6, Dave Larsen decided to back out of the project.  The team now called
MAREX-NA was able to immediately gather funding to complete the project and
has now finished all four (4) flight ready SSTV systems.  The MAREX-NA team
has also received a Launch Date.
(some  of  the details of the project can be found on the MAREX-NA web page
http://www.geocities.com/CapeCanaveral/Hangar/7355/sstv_proj.htm)

Frequency:
A lot of planning has gone into the frequency planning of the SSTV project.
Fortunately the project is designed to be frequency adjile.  Below are just
some  of  the possible frequency options.  The engineering team at MAREX-NA
are  more than willing to open a dialog to discus frequency options for the
upcoming project.

I would like to present a few frequency options for the SSTV project for
the Russian Space Station Mir.  The frequencies chosen are based ITU
regulations, Mir Antenna access,  Existing Mir Amateur Radio projects and
interference issues from Ground and Mir communications systems.

Mir currently has three dual-band antennas dedicated for Amateur radio
access.  One antenna is located in the Mir-core module and supports
2-meters and 70 cm.  The next two antennas are located in the Proidia
module. Both of these antennas are the same type of dual band antenna,
2-meters and 70 cm.  One antenna is connected to the SAFEX 70 cm
transmitter and the other is connected to the SAFEX 70 cm receiver.  The
transmitter antenna is also connected to a Diplexor 2-meter filter, built
into the SAFEX repeater.  This connection allows easy access to the two
meter portion of  that antenna.  This port is currently being used as the
back up antenna
for the Mir PMS (December 97 - Present).

Option #1 70 cm
Assumes the following configuration:
A.   The Icom SAFEX II repeater is in normal operation ( Transmit 437.925,
437.950 FM Split, Receive 435.725, 425.925)
B.   The Kenwood PMS is in normal operation (145.985 FM Simplex)
C.   SSTV configured for frequency 435.050, 435.075, 435.100, 435.150  See
Note: 1
D.   or SSTV Transmit  configured for 437.900, 437.975

The SSTV system will need to be connected to the Dual band antenna in the
Mir-Core, via
the existing Diplexor filter.  This configuration should be able to support
all three projects simultaneously, 2-meter PMS , the SAFEX Repeater and the
SSTV system without any restrictions.
We do not want generate interference to the SAFEX II repeater system.  The
frequencies
chosen will keep the SSTV transmitter far enough away from the SAFEX
receiver frequency
to avoid any interference.  The Cavity filters built into the SAFEX will
prevent the SSTV down
link channel from de-sensing the repeaters input frequency.  The down link
channels are not currently used by any active amateur radio satellite.
Stations monitoring the SSTV signals will need to compensate for
the +/- 10 k Doppler swing.  Terrestrial test have shown that frequency
errors of less than 6k can offer good pictures.
Limitation:  None

Option #2 2-Meters
Assumes the following configuration:
A.   The Icom SAFEX II repeater is in normal operation (437.925, 950)
B.   The Kenwood PMS is in normal operation (145.985 FM Simplex)
C.   SSTV configured for frequency 144.325 Simplex See Note: 1

In this configuration, the PMS is connected to the Mir-core antenna system.
The MIREX-SSTV is connected to the Built-in SAFEX II 2-meter antenna port
in the
Priorida module.  The SSTV system will not cause any interference to the
SAFEX II repeater system.
The 2-meter down link channel is not currently used by any active amateur
radio satellite.
The frequency is also as far as possible away from the 2-meter PMS.  There
will a limited amount
of interference to the 2-meter PMS.  The exact amount of interference is
difficult to calculate. The 2-meter PMS will have the Mirex-DCI filter
installed on the antenna port.  This filter begins to attenuate signals
below 144.500.  The SAFEX II 2-meter Diplexor port also contains a pass
band filter.  The PMS and SSTV antennas are over 40 feet apart. The
interference may not be significant.  Strong uplink signals will be able to
over ride the 34 seconds of SSTV de-sense.   The De-sense will only affect
low ERP stations working the PMS.  If a low ERP station is de-sensed, it
will only last for 34 seconds every 120 second cycle, then PMS Retry
feature will pick up where it left off.  The reason for the PMS on 145.985
Simplex and the SSTV on 144.325 simplex is to keep the two channels as far
apart as possible.  (note, ITU will allow down to 144.025).
Stations receiving the SSTV signal will not be affected by the +/- 4k
Doppler swing. Terrestrial test have shown that frequency errors of less
than 6k can offer good pictures  A station monitoring 144.325 should be
able to copy good images without compensating for Doppler shift.


Option #3 70 cm
Assumes the following configuration:
A.   The Icom SAFEX II repeater is shutdown and the antenna is used for
SSTV
B.   The Kenwood PMS is in normal operation (145.985 FM Simplex or any
2-meter mono-band frequency)
C.   SSTV configured for a down link frequency in the 70cm band, the
up-link frequency can be either in the 2-meter band or in the 70cm band.
There are many options with this combination.

In this configuration, the PMS is connected to the Mir-core antenna system
with the DCI filter.
The MIREX-SSTV is connected to the dual-band antenna formally use by the
SAFEX II repeater.  This configuration should only be used if the SAFEX
Repeater is no longer functional.


Note:  1 The following frequencies are being used as down links
UO-11     437.025
UO-22 437.120
UO-23 437.175
UO-25 437.175
AO-10 is using 437.030 - 437.180 as a transponder input.  Since AO-10 is
off the air 90% of the time.
The use of this part of the band for SSTV down links should not cause long
term problems for AO-10



Frequencies from the Toronto Amsat meeting.

First  I  need  to  apologize for not being present at the Toronto meeting.
The   MIREX   team  just  did  not  have  the  funding  available  to  send
representatives  to conferences.  All of our funding which is mostly out of
pocket  expenses was being used to complete the three projects that we were
working  on at that time (Kantronics KPC-9612 upgrade-Installed on Mir, and
DCI  QRM  filter-Delved  to  Mir).   If  a representative of MIREX had been
present, the frequencies chosen could have been more functional.


Toronto MANNED SPACE MISSION FREQUENCY PLANS

Downlink:                                                    145,800  MHz

Alternative downlinks for special
event/emergency use only                               145,8125 MHz
                                                                  145,990
MHz

Uplink:                                                      144,490  MHZ
Additional uplink IARU Region 1 only          145,200  MHZ

Additional UPLINKs required                             144,470  MHZ
                                                                  144,450
MHZ

There are three problems with this frequency plan:
1.   The people who chose the frequencies did not have the years of
experience of actually supporting the equipment on board the Mir Station.
The Mirex team had spent over 6 years continuously supporting the crews
in-flight.  To properly choose good working frequencies you need to know
the antenna placement and number and type of existing Commercial VHF
transmitters.  More than one astronaut has commented that Mir has more
transmitters per square foot than any place in the world.  The people at
Toronto did a fair job in choosing frequencies, however they just did not
understand all of the related issues.
2.   De-Sensing:  Mir has several VHF transmitters operating near the
2-meter band (121.750, 130.167, 143.625, 166.000, etc.).  The transmitter
which causes the most problems to the 2-meter Amateur Radio Station is the
one on 143.625.  This specific transmitters causes the PMS to go Deaf every
time the 143.625 transmitter is active.  This is why, MIREX built and flew
a special 5 pound cavity filter for the 2-meter PMS station.  Even with the
special filter, the PMS will still be de-sensed if the PMS Receive
frequency is placed too close to the 143.625 commercial transmit frequency.
This is the primary reason why Mirex has experimented with the 145.985
frequency.  Its far way from QRM caused by the commercial transmitter.  At
the Toronto meeting, 144.450, 144.470 & 144.490 were selected as UPLINK
channels.  Because of the De-sensing problem, the area 144.300 through
144.500 is best suited as a DOWNLINK band and not an UPLINK band. The
International Space Station will have a similar problem, because the same
commercial transmit frequencies are expected to be used.
3.   Expandability:  There is not much room for experiment expansion.


Benefits to Amsat:
The public wants to see a string of success stores on a regular basis.  The
RS-17-1  project  last  winter  was  a great success and generated a lot of
interest world wide.  The follow-on RS-17-2 project scheduled for this fall
is  also  expected  to  be  an attention getter.  These successful projects
keeps  peoples  interest  in  Amateur  Radio Satellite experimentation.  It
challenges  their  curiosity and gets worked into school curriculums.  Many
schools  around the world would tune into the Beep, Beep of Sputnik RS-17-1
and listen.

The  Mir  SSTV  experiment will also generate a lot of positive interest in
school  educational  programs.  Now for the first time school children will
not  only  able  to hear the crews talking during school schedules, but the
students  will  be  able  to see some of the 720 images per day coming from
Mir.   Web pages around the world will store the best images for schools to
log  into  and view.  Many schools are expected add Amateur Radio equipment
to the schools so the can down load and display the images live.

The  success  of the Mir Amateur Radio and other Russian Satellite projects
has  been  very  good  for  Amateur  Radio  and Amsat.  Over 75% of the new
Amateur  Radio  satellite  operators  started  their  operations by using a
Russian  sponsored  satellite.   Most  of  those  people began by using the
Russian  Space  Station  Mir  Personal Message System.  The Mir SSTV system
will  help  keep  the  people  interested in Amateur Radio Satellites while
Amsat builds phase 3D.

Many  of the people who started on Mir have also become Amsat Members.  The
more  successful the Amateur Radio projects on Mir, the more Amsat members,
and  the more funds Amsat will have for P3D.  You can think of the Mir SSTV
project as a form of fund raiser for P3D.

Conclusion:

I only see good things coming from this project.  It benefits everyone:
Amsat will get more members
Amsat will get more interest in P3D and more donations
School  children  will become more interested in Space exploration by being
able for the first time
to  See the crew and their experiments (including the pet lizards and other
pets on Mir).
People  who  are  not currently Amateur radio operators, may become Amateur
Radio operators.
We will learn more about how to design better projects for ISS.
And the list goes on and on.

I am looking forward to hearing from responsible parties on internationally
coordinating the Mir SSTV project.

Sincerely


G.   Miles Mann WF1F